Liquid Crystal Display (LCD), Organic Light Emitting Diode (OLED) and other flat panel displays have been gradually replaced the CRT displays and become a mainstream of the display devices. The LCD or the OLED is generally manufactured on a sheet glass (such as a sheet glass having a 0.5 mm thickness). In the manufacture processes of the LCD or the OLED, a process of aligning the two sheet glasses and gluing the two for implementing package to the LCD or the OLED is required. The machine employed for this process is so called VAS (Vacuum Alignment System).
Please refer from FIG. 1 to FIG. 3. The sheet glass alignment system according to prior art comprises: an upper alignment platform 100 and a lower alignment platform 300 which are oppositely located, and the upper alignment platform 100 is capable of moving up and down relative to the lower alignment platform 300; the upper alignment platform 100 comprises a plurality of first air holes 110, penetrating upper and lower surfaces of the upper alignment platform 100, and being arranged in array, a plurality of first stepped holes 130 penetrating upper and lower surfaces of the upper alignment platform 100 and offsetting from the first air holes 110, first fitting seats 150 fixedly located in the wide portions 134 at the bottoms of the first stepped holes 130, first sucking discs 170 installed on the first fitting seats 150 and first rubber elements 190 installed on the first fitting seats 150 inside the first sucking discs 170; the first rubber elements 190 are hollow and the thickness is smaller. Each of them comprises an open, and the open is connected to the first stepped hole 130 through the central hole of the first fitting seat 150. The structure of the lower alignment platform 300 is opposite to the upper alignment platform 100, and it comprises a plurality of second air holes 310, penetrating upper and lower surfaces of the lower alignment platform 300, and being arranged in array, a plurality of second stepped holes 130 penetrating upper and lower surfaces of the lower alignment platform 300 and offsetting from the second air holes 310, second fitting seats 350 fixedly located in the wide portions 334 at the tops of the second stepped holes 330, second sucking discs 370 installed on the second fitting seats 350 and second rubber elements 390 installed on the second fitting seats 350 inside the second sucking discs 370; the second rubber elements 390 are hollow and the thickness is smaller. Each of them comprises an open, and the open is connected to the second stepped hole 330 through the central hole of the second fitting seat 350.
The sheet glass alignment method utilizing the aforesaid sheet glass alignment system comprises steps of:
step 1, providing an upper substrate 200 and a lower substrate 400 to be aligned;
step 2, a robot arm is employed to transfer the upper substrate 200 right below the upper alignment platform 100; and the robot arm lifts the upper substrate 200 upward, and meanwhile, the first air holes 110 are vacuumed to attach the upper substrate 200 to the upper alignment platform 100; finally, the robot arm is moved out and the first air holes 110 are charged to return to 1 atm, and the upper substrate 200 is attached by the first sucking discs 170;
step 3, a robot arm is employed to transfer the lower substrate 400 right above the lower alignment platform 300; and the robot arm descends the lower substrate 400 downward, and meanwhile, the second air holes 310 are vacuumed to attach the lower substrate 400 to the lower alignment platform 300; finally, the robot arm is moved out and the second air holes 310 are charged to return to 1 atm, and the lower substrate 400 is attached by the second sucking discs 370;
step 4, please refer to FIG. 4, slowly moving the upper alignment platform 100 downward until the upper substrate 200 and the lower substrate 400 are aligned;
step 5, please refer to FIG. 5, respectively charging the first and the second rubber elements 190, 390 through the first and the second stepped holes 130, 330, to bubble the first and the second rubber elements 190, 390. Ultimately, the upper substrate 200 and the lower substrate 400 are removed away from the first and the second sucking discs 170, 370;
step 6, lifting the upper alignment platform 100 to return back to the original position;
step 7, extracting out the upper and the lower substrates 2, 4 which have been aligned with the robot arm.
In the sheet glass alignment method according to prior art, the method of bubbling is employed to move the upper and the lower substrates 200, 400 away from the upper and the lower alignment platforms 100, 300. The advantage of such method is that the structure is simple and the operation is easy. The drawback is the ages of the first and the second rubber elements 190, 390. Just like the hydrogen balloons, they will be deformed after the repeated charges and discharges many times. As shown in FIG. 5, if the age degrees of the first and the second rubber elements 190, 390 are different, it leads to that some bubbles will large and some bubbles will be small under the same pressure. The pressure applied to the upper substrate 200 or the lower substrate 400 can be uneven to cause that the pressures to some positions of the upper and the lower substrates 200, 400 are large and the pressures to some positions might be small. According bends and deformations occur to decrease the production yield of the panel display devices.